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Liu Zi-zhen - One of the best experts on this subject based on the ideXlab platform.

Yin Xia - One of the best experts on this subject based on the ideXlab platform.

  • A kind of new devices for 72%(wt) flake Caustic Soda production
    Chlor-alkali Industry, 2004
    Co-Authors: Yin Xia
    Abstract:

    A kind of new devices for 72%(wt) flake Caustic Soda production is introduced.Caustic Soda is concentrated from 30%(wt) to 50%(wt) by rotary film-evaporator,and then from 50%(wt) to 72%(wt,flake) in the devices by external-heating evaporator.The experiment for Caustic Soda concentrating is carried out in the test device of 1 m~2 rotary film-evaporator,and the effect of flow,rotating speed,viscosity on coefficency of heat transfer is studied.The actual production application shows that the production capacity of a set of 50 m~2 device is 10 kt/a(equal to 7 kt/a of 100% Caustic Soda).

  • 72 wt% flake Caustic Soda production plant equiped with thin film evaporator
    Chlor-alkali Industry, 2003
    Co-Authors: Yin Xia
    Abstract:

    The flow path,main equipment,design calculation and running situation of 72 wt% flake Caustic Soda production plant equiped with film evaporator were introduced.This process realized the continuous evaporation of Caustic Soda from 30 wt% to 72 wt%.Meanwhiles,the working condition was improved and flake Caustic Soda with high quality was produced with high production efficiency.The practical production proved that the capacity of a set of 50 m 2 evaporator with external heating unit was 10 thousand tons of 72 wt% flake Caustic Soda per year.

Gao Shubin - One of the best experts on this subject based on the ideXlab platform.

Liu Maosheng - One of the best experts on this subject based on the ideXlab platform.

  • decomposing scheelite and scheelite wolframite mixed concentrate by Caustic Soda digestion
    Journal of Central South University of Technology, 2003
    Co-Authors: Sun Peimei, Li Honggui, Li Yunjiao, Sun Zhaoming, Huo Guangsheng, Zhao Zhongwei, Liu Maosheng
    Abstract:

    Scheelite and scheelite-wolframite mixed concentrates with different grades were decomposed by Caustic Soda digestion, and the effects of Caustic Soda (NaOH) dosage, the ratio of water to ore and the stirring rate on tungsten recovery were studied. The results show that under the conditions that the ratio of water to ore is 0.8, stirring rate is 500 r · min−1 and the heating time is 2.0 h at 160 °C, the recovery of tungsten reaches 98% for scheelite (w(WO3) is 65.04%) and wolframite containing high proportion of calcium (w(WO3) is 65.58%, w(Ca) is 7.53%), when Caustic Soda dosage is 2.2 and 2.0 times of theoretical value, respectively; the recovery of tungsten can be more than 98%, 98% and 96% respectively for low-grade scheelite-wolframite mixed concentrate with 55.78%, 45.32% and 25.21% WO3, when Caustic Soda dosage is 2.6, 3.2 and 5.5 times of theoretical value, respectively.

K Kovacevic - One of the best experts on this subject based on the ideXlab platform.

  • influence of oxalic acid on the kinetics of al oh 3 growth from Caustic Soda solutions
    Hydrometallurgy, 2004
    Co-Authors: Irena Nikolic, D Blecic, Nada Blagojevic, V Radmilovic, K Kovacevic
    Abstract:

    Abstract Crystallization of Al(OH) 3 from Caustic Soda solutions is an important part of the Bayer process for alumina production. Nucleation, agglomeration and crystal growth processes occur simultaneously during crystallization of Al(OH) 3 and have different effects on the final product. In this study, we have investigated the influence of oxalic acid on the kinetics of Al(OH) 3 crystal growth. The results have shown that the overall growth rate of Al(OH) 3 crystals increased with increase of temperature of crystallization and decreased with Caustic Soda concentration, both in the presence and absence of oxalic acid. However, the presence of oxalic acid reduces the overall growth rate of Al(OH) 3 compared to the overall crystal growth rate from the pure Caustic Soda solutions, and the reduction is greater as the concentration of oxalic acid increased. In other words, the oxalic acid has the inhibitory influence on Al(OH) 3 crystal growth. The effectiveness of the oxalic acid on the Al(OH) 3 growth can be represented through a modified Langmuir adsorption isotherm, and adsorption of admixture on the surface of growing Al(OH) 3 crystals is favoured with a decrease in temperature and with an increase in oxalic acid concentration. Relatively high crystal growth rates (between 8 and 22 μm/h) result from an agglomeration process that could not be prevented because of the presence of small seed Al(OH) 3 particles and the newly formed Al(OH) 3 particles through the nucleation process. Investigation of agglomeration and nucleation processes has shown that agglomeration increased with increasing temperature and decreasing Caustic Soda concentration, while the nucleation process can be increased with decreasing temperature and Caustic Soda concentration.